How to Plan for Continuous (Exterior) Insulation on an Existing Homes

This post first appeared on the Green Building Advisor website.

When I purchased my small 1950’s vintage Cape Cod home in 2018, I knew I had a lot of work to improve its performance and comfort.  I was planning a multi-year, self-performed (and solo), deep energy retrofit.  A case study where I could learn and share the difficulties of such an endeavor. 

One of my goals was to improve the insulation levels of both the walls and roof.  I went back and forth trying to decide if I should add a layer of continuous insulation to the exterior.  After all, I was going to remove the existing siding and replace all the windows.  In the end, I decided against it.  The gable ends of my roof have no eave (see photos below), adding exterior insulation would have required me to rebuild a portion of the recently re-shingled 12/12 pitched roof.  I now regret that decision, more on that later.

Continue reading “How to Plan for Continuous (Exterior) Insulation on an Existing Homes”

What You Need to Know About Continuous Insulation-Part 2

This post first appeared on the Green Building Advisor website.

In the first part of this continuous insulation blog, we covered building codes and some building science and how they relate to CI.  This second part will discuss some of the difficulties many builders have with how the details work.

I remember my first time using continuous insulation in a new home.  I had many questions; where to put the WRB, how to attach the cladding, how to address the windows and doors, and how much insulation to use.  That home is now more than a dozen years old without any complaints from the homeowner.  Would I change some of the details I implemented on that first CI home?  Absolutely!  But the design and execution all those years ago seems to be performing.

Photo by Armando Cobo

Continue reading “What You Need to Know About Continuous Insulation-Part 2”

What You Need to Know About Continuous Insulation-Part 1

This post first appeared on the Green Building Advisor website.

Living in a very cold climate where wintertime temperatures colder than -20°F aren’t uncommon, you would think contractors and homeowners in my market would be excited to use continuous insulation (CI) on every new home under constructed along with every existing home having the exterior cladding replaced.  In reality, I rarely see either happening.  Part of the reasoning, my state and local building codes don’t require CI.  Cost is another driving factor.  As both homeowners and builders become better educated on the benefits of CI, this should start changing, I’m advocating for its inclusion on projects I’m involved in.

There are many reasons to use continuous insulation.  Reduced energy consumption is one benefit, though lowering heating and cooling costs are, in my opinion, less important and a secondary reason to add CI.  Improving comfort (thermal and sound) and expanding durability are more important.  (I’ll get into durability in detail later in this article.)  Building codes have begun to align with building science and we are seeing more areas across the country adopt continuous insulation as part of the energy code.  The scary part for most builders is the unfamiliarity of installing insulation on the exterior of a wall.  What insulation can be used?  What thickness and R-value are required?  How do I detail window and door openings?  How do I secure the insulation?  How do I attach the cladding?  Where does the house wrap go?  What about other penetrations such as exhaust vents and electrical penetrations?  What about the vapor retarder?  We will be discussing these topics and more over the next two articles.  In this post, we will be discussing the building code requirements along with the building science principles covering CI. Continue reading “What You Need to Know About Continuous Insulation-Part 1”

The Thermal Bridge

Thermal imaging is an awesome tool, it can be used to find areas of missing insulation and other temperature anomalies in the building shell.  It can help us find issues with electrical, plumbing and heating systems.  And when used in conjunction with a blower door, we can often “see” the air leaks.  The photo below was taken without the assistance of a blower door, I was at this new home to conduct a blower door, but the test hadn’t begun at the time this photo was taken, can you say thermal bridge!

Continue reading “The Thermal Bridge”